Latin name of the genus and species of the plant claimed: Prunus salicina. 
Variety denomination: xe2x80x98Suplumtwentyeightxe2x80x99.
This invention relates to the discovery and asexual propagation of a new and distinct variety of plum tree, herein after referred to by the cultivar name xe2x80x98Suplumtwentyeightxe2x80x99. The variety originated by hybridization performed by Bruce Mowrey. The new variety was first selected and evaluated by David Cain on Sun World Experimental Ranch 75 near Wasco, Calif. in Kern County. The new variety is characterized by heavy and consistent production of large (65 mm diameter), firm fruit that ripens early, during the middle of June in the Bakersfield, Calif. area. Fruit of xe2x80x98Suplumtwentyeightxe2x80x99 have smooth black-colored skin and flesh that develops red color as they ripen. Eating quality is excellent with 18xc2x0 brix, plentiful juice, and skin flavor that is neutral.
The parent varieties were first crossed in 1993, with the date of planting of February, 1994, and the date of first flowering being March, 1997. The new plum variety was first asexually propagated by Terry Bacon near Wasco, Kern County, Calif. in December, 2001, by grafting onto Nemaguard rootstock.
The seed parent is Sun World breeding selection, xe2x80x9891P-001xe2x80x99 (unpatented), which was selected from a progeny of Sun World breeding selection xe2x80x98232-205xe2x80x99 (unpatented) crossed with pollen from Sun World selection xe2x80x98275-136xe2x80x99 (unpatented). The new variety is distinguished from its seed parent by ripening 16 days later and having fruit that averages 65 mm as compared to xe2x80x9891P-001xe2x80x99 with 55 mm. Additionally, the new variety develops red flesh as it ripens while xe2x80x9891P-001xe2x80x99 has amber flesh. The pollen parent was an unknown Sun World breeding selection.
The new variety most nearly resembles xe2x80x98Suplumelevenxe2x80x99 (U.S. Plant Pat. No. 4,902). It may be distinguished from xe2x80x98Suplumelevenxe2x80x99 by ripening 20 days earlier. The new variety ripens approximately the same time as xe2x80x98Santa Rosaxe2x80x99 (unpatented) but develops red flesh while xe2x80x98Santa Rosaxe2x80x99 has amber-colored flesh, and is larger (65 mm compared to 55 mm diameter with xe2x80x98Santa Rosaxe2x80x99).
The new plum tree variety cv. xe2x80x98Suplumtwentyeightxe2x80x99 has been shown to maintain its distinguishing characteristics.